Electric relay



ELECTRIC LAMP 8c DISCHARGE I DEICES, SYSTEMS. f 6? Aug 25 was. 1,550,877

E. L. CHAFFEE ELECTRIC RELAY Original Filed March 10, 1916 L 0 as 3.5 3Li 39, .5 9 6 t WITNESS 64 Patented Aug. 25, 1925.

UNITED STATES PATENT OFFICE.

EMORY LEO-N CI-IAFFEE, OF BELMONT, MASSACHUSETTS, ASSIGNOR TO JOHN HAYSHAMMOND, 3B,, OF GLOUCESTER, MASSACHUSETTS.

nnno'rnrc RELAY. I

Application filed March 10, 1916, Serial No. 83,327. Renewed September11, 1923.

To all whom it may concern:

Be it known that I, EMORY LEON CHAFFEE, a citizen of the United States,and a resident of Belmont, in the county of Middlesex and State ofMassachusetts, have invented certain new and useful Improvements inElectrio Relays, of which the following is a specification.

One of the objects of this invention is to provide in an electric relayincluding a detector improved means for reducing the persistence of theoperation of the detector after the impulse which initiated suchoperation has ceased.

Further objects of this ,invention are to provide in an electric relayincluding a detector, improved means for increasing the sensitiveness ofthe detector by permitting the detector to be normally adjusted veryclose to the point of breaking down; and to provide other improvementsas will appear hereinafter.

In the accompanying drawing, Fig. 1 is a diagrammatic illustration of anelectric relay constructed in accordance with this invention; and Figs.2 and 3 are fragmentary diagrammatic views of modified forms of thesame.

Referring to the drawings, one embodiment of this invention comprises agaseous detector of the mercury type including the usual or any suitableair tight glass bulb or container 10, from the interior of whichpractically all gases have been exhausted. The lower portion of the bulbis extended downwardly to form a well 11 which contains mercury forminga cathode 12. The lower portion of the bulb is also provided with theusual reservoir 13 containing mercury 14.

Within the bulb 10 and spaced slightly above the mercury cathode 12 is aflat horizontal annular metal plate 20 forming an anode which issupported in a fixed position by the inner end of a substantially rigidmetal conductor 21, the outer end of which projects tightly through thebulb 10 and is sealed in. position. The portion of this conductor 21within the bulb 10 is preferably surrounded by a glass tube 22 or otherinsulator.

In the upper portion of the bulb 10 is a flat horizontal circular metalplate 25 forming an electrode which is supported in a fixed positio 0L il-16 1QW61 end. of a vertl al rigid metal conductor 26, the upperportion of which projects tightly through the bulb 10 and is sealed inposition. The portion of the conductor 26 within the bulb 10 ispreferably surrounded by a glass tube 27 or other insulator. J

Extending through the mercury cathode 12 is a vertical conductor 30, theupper end of which is preferably provided with a platinum tip 31 whichprojects slightly above the mercury and in alinement with the centralopening in the anode 20 to render the oathode spot of the arc dischargestationary. The lower end of the conductor 30 projects tightly throughthe wall of the well 11 and is sealed in position.

The bulb 10 and contained elements are arranged to control an outgoingor controlled circuit including a source of alternating potential 35,one pole or brush 36 of which is connected by a conductor 37 with thelower end of the conductor 30, and the other pole or brush 38 of whichis connected by a conductor 39 and through the conductor 26 with theuppermost electrode 25. The conductor 39 extends through and controls arelay 40 or any other suitable device.

A battery has a positive pole connected through a conductor 46,regulating or variable resistance 47, inductance 48 and conductors 49and 21 with the anode 20. A negative pole of the battery is connected bya conductor 50 and the conductors 37 and 30 with the mercury cathode 12.

Fixedly secured within the bulb 10 and spaced a suitable distance belowthe terminal or electrode 25 is a flat circular perforated metallic gridor potential gradient changing means of the usual or any suitable construction. From this grid leads a conductor 56 to one end of aninductance 57 the other end of which is connected by a conductor 58 toone end of a high resistance 60. The proper magnitude of this highresistance 60 should be experimentally determined for each particularbulb 10. It has been found that in ordinary cases and with such bulbs asare generally used the best value of this high resistance 60 ranges froma few thousand to twenty or thirty thousand ohms, depending upon thebulb used. Instead of connecting the resistance 60 between the conductor58 and the contact 61, it might be inserted in the conductor 56, asshown in Fig. 2. In ny a he resistance, 60 may be either a non-inductiveresistance, as shown in Figs. 1 and 2, or an inductive resistance, asshown in Fig. 3, but preferably a noninductive resistance. The other endof the high resistance 60 is connected to a movable contact 61 whichadjustably engages a stationary resistance 62 forming a potentiometer.One end of the latter resistance 62 is connected by a conductor with anegative pole of the battery 45, while the other end of the resistance62 is connected by a conductor 64 and adjustable contact 65 with apositive pole of the battery 45. A condenser 66 is interposed betweenthe conductors 56 and 58, and cooperates with the inductance 57 informing an oscillatory circuit.

The circuit including the inductance 57, high resistance 60, variableresistance 62, and conductor 63, may be designated the in coming orcontrolling circuit, and the whole combination thus far describedconstitutes an electric relay arranged to control a secondary relay 40.

The inductance 57 forms the usual secondary coil of a tuningtransformer, the primary coil or inductance '70 of which is looselycoupled to the secondary inductance 57. The primary inductance 70 formspart of an antenna or open aerial circuit 71 which is grounded throughan adjustable contact 72 and conductor 7 3.

In the operation of a relay constructed as hereinbefore described, aquiet arc is normally maintained between the mercury cathode 12 and theannular anode 20 by the battery 45. The grid is normally maintained at acertain definite potential between that of the anode 20 and that of themercury cathode 12 by a suitable adjustment of the potentiometer 61, 62,and the adjust-able contact 65. Under these conditions, the distributionof the potentials in the bulb 10 is such that normally substantially nocurrent flows from the source of alternating potential 85 through therelay 40 and bulb 10, but if the potential of the grid 55 be evenslightly increased, as for instance in a well known manner in responseto an impulse of radiant energy received by the antenna 71, then thenormal apparent resistance of the interior of the bulb 10 will beapparently decreased in a well known manner and a rectified current willflow from the source of alternating potential through the conductor 39and relay 40 to the electrode 25 from which the greater portion of thecurrent will pass through the interior of the bulb 10 to the mercurycathode 12 andthenceback through the conductor 37 to the source 85.While this is taking place, however, some of the rectified current willbe passing from the electrode 25 to the grid 55 and then through theside or grid circuit 56, 57, 58, 60, 61, 62, 63 and 37 and back throughthe mercury cathode 12. It is thought that in old forms of detectors asheretofore constructed and connected, this flow into the grid 55 andthrough the grid circuit has caused an undesirable modification in thedistribution of potentials in the bulb 10 which has resulted in asufficient increase in the potential of the grid 55 to cause thedischarge from the electrode 25 to persist even after the excitationwhich has caused the initial increase in the potential of the grid hasceased. The result of this action of the grid circuit has been to causethe interior of the bulb 10 to remain in a conductive condition and topermit a rectified current to flow through the bulb 10 from the source35, after the cessation of the impulse which initiated the operation 01the detector, and consequently the detector has thus been renderedinoperative to respond to a second impulse.

One of the advantages of this improved construction, is that the highresistance which has been inserted in the grid circuit, so muchincreases the resistance of the grid circuit, that the amount ofrectified current which is shunted oil through the grid circuit isgreatly reduced and the tendency of the conductivity of the interior ofthe bulb to persist is consequently greatly reduced, and to such anextent as to practically avoid having the detector continue to operateafter the cessation of the impulse which has initiated its operation.

A further advantage of this improved construction is that the use of thehigh resistance 60 in the grid circuit makes it possible to adjust thenormal voltage of the grid much nearer to the break-down-potential, or,to the point of breaking down, thus greatly increasing the sensitivenessof the bulb The addition of the high resistance 60 does not in any wayinterfere with the effective operation of the detector. Since normallythere is practically no flow of current in the grid or incoming circuit55, 56, 57, 58, etc., the presence of the high resistance 60 in thiscircuit does not cause any drop in potential, so that the potential ofthe grid 55 will be governed by the. potentiometer 61, 62 as before.

Although this invention has been shown as applied in a mercury vapordetector and only in a single construction and arrangement ofconnections, it is to be understood that the invention is not limited inits application to any particular form of gaseous or other detectors orto any particular construction or arrangement of connections, but mightbe applied in various forms of detectors and with various connectionswithout departing from the spirit of the invention or the scope of theappended claims.

Having thus fully described this invention, I claim:

1, An electri rel y c mpris g a control- ELECTRIC LAMP 8c DISCHARGE.

"7 OW a ling circuit including in series potential gradient changingmeans, a high resistance, and means arranged to respond to externalvariations of potential, and a circuit controlled by said firstmentioned circuit and including a source of potential, said secondmentioned circuit being so adjusted that normally substantially nocurrent flows therethrough.

2. An electric relay comprising a control ling circuit including inseries potential gradient changing means, a high resistance,

and means arranged to respond to electrical impulses, and a circuitcontrolled by said first mentioned circuit and including a source ofpotential, said second mentioned circuit being so adjusted that normallysubstantially no current flows therethrough.

3. An electric relay comprising a container, a cathode, an anode,potential gradient changing means, and an electrode spaced in saidcontainer, means for maintaining an electric are between said cathodeand said anode a controlling circuit connecting said potential gradientchanging means and said cathode and including in series with said meansa high resistance and means arranged to respond to external electricalimpulses, and a circuit including said cath ode, said electrode and asource of potential, the construction and arrangement being such thatnormally substantially no current flows through said second mentionedcircuit, and said resistance being so proportioned that substantially norectified current will be permitted to pass between said potentialgradient changing means and said cathode through said controllingcircuit.

4. An electric relay comprising a container, a cathode, an anode,potential gradient changing means, and an electrode spaced in saidcontainer, means for maintaining an electric are between said cathodeand said anode a controlling circuit connecting said potential gradientchanging means and said cathode and including in series with said meansa high impedance and means arranged to respond to external electricalimpulses, and a circuit including said cathode, said electrode and asource of potential, the construction and arrangement being such thatnormally substantially no current flows through said second mentionedcircuit, and said impedance being so proportioned that substantially norectified current will be permitted to pass between said potentialgradient changing means and said cathode through said controllingcircuit.

Signed at Cambridge in the county of Middlesex and State ofMassachusetts this second day of March A. D. 1916.

EMORY'LEON'GHAFFEE.

